chocolate vs deep brown

chocolate and deep brown both are nouns.

Word	Noun	Adjective	Verb	Adverb
chocolate	Yes	No	No	No
deep brown	Yes	No	No	No

As nouns, chocolate and deep brown are synonyms defined as:

Other synonyms of chocolate include burnt umber, coffee, umber.

chocolate (noun)	deep brown (noun)
a medium brown to dark-brown color	a medium brown to dark-brown color
a food made from roasted ground cacao beans
a beverage made from cocoa powder and milk and sugar; usually drunk hot